Differential quenching method for large-diameter whole ledeburitic steel cold roll

A technology of ledeburite steel and differential temperature quenching, which is applied in furnaces, heat treatment equipment, heat treatment furnaces, etc., and can solve problems such as cracking

Active Publication Date: 2011-05-04
SHANXI BUYEASY MACHINERY MFG
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0003] In order to solve the problem that the existing large-diameter integral ledeburite steel cold rolls are prone to cracking after ...

Method used

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  • Differential quenching method for large-diameter whole ledeburitic steel cold roll
  • Differential quenching method for large-diameter whole ledeburitic steel cold roll
  • Differential quenching method for large-diameter whole ledeburitic steel cold roll

Examples

Experimental program
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Effect test

Embodiment 1

[0008] The large-diameter overall ledeburite steel cold rolling roll is a die steel Cr12MoV with a diameter of 300mm and a low-magnification structure of the billet of grade 4. The preheating temperature is selected for isothermal preheating, and then quickly heated to the quenching temperature and then kept for heat preservation; then the cooling temperature is selected for isothermal Cooling, and finally cooling in the air, the preheating temperature is 950°C, and the cooling temperature is 250°C. After isothermal preheating, the heating rate to the quenching temperature is 100°C / h, and the holding time after heating to the quenching temperature is 1.5h. During the specific implementation process, the quenching temperature is 1050° C., and the time for isothermal preheating and isothermal cooling is 3 h and 1.2 h, respectively.

Embodiment 2

[0010] The large-diameter overall ledeburite steel cold rolling roll is a high-speed steel W2Mo8Cr4V with a diameter of 250mm and a billet low-magnification structure of 3.5. The preheating temperature is selected for isothermal preheating, and then quickly heated to the quenching temperature and then kept for heat preservation; then the cooling temperature is selected for isothermal Cooling, and finally cooling in the air, the preheating temperature is 1100°C, and the cooling temperature is 250°C. After isothermal preheating, the heating rate to the quenching temperature is 100°C / h, and the holding time after heating to the quenching temperature is 1.2h. During the specific implementation process, the quenching temperature is 1180° C., and the time for isothermal preheating and isothermal cooling is 2.5 h and 1 h, respectively.

Embodiment 3

[0012] The large-diameter overall ledeburite steel cold rolling roll is a semi-high-speed steel Cr8MoWSiV3 with a diameter of 350mm and a billet low-magnification structure of grade 3. The preheating temperature is selected for isothermal preheating, and then rapidly heated to the quenching temperature and then kept for heat preservation; then the cooling temperature is selected for cooling. Isothermal cooling, and finally cooling in air, the preheating temperature is 1070°C, and the cooling temperature is 250°C. After isothermal preheating, the heating rate to the quenching temperature is 100°C / h, and the holding time is 2 hours after heating to the quenching temperature. During the specific implementation process, the quenching temperature is 1130° C., and the time for isothermal preheating and isothermal cooling is 3.5 h and 1.5 h, respectively.

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Abstract

The invention relates to a heat treatment method for a ledeburitic steel cold roll, in particular to a differential quenching method for a large-diameter whole ledeburitic steel cold roll, solving the problem that the existing large-diameter whole ledeburitic steel cold roll is easily ruptured after being quenched. The method comprises the following steps: selecting a pre-heat temperature to perform isothermal preheating; quickly heating to a quenching temperature, and preserving the temperature; selecting a cooling temperature to perform isothermal cooling; and cooling in the air, wherein the range of the preheat temperature is more than the critical transition point of complete austenitizing temperature or/and less than the actual quenching temperature 30 DEG C, and the range of the cooling temperature is more than the martensite point and less than the martensite point plus 100 DEG C. In the method, the problem that the existing large-diameter whole ledeburitic steel cold roll is easily cracked after being quenched can be solved through a reasonable design, the whole body is completely quenched and hardened, the hardness of a working layer reaches 60 to 67 HRC, and the hardnessgradient between the cold roll center and the surface layer is less than 10HRC.

Description

technical field [0001] The invention relates to a heat treatment method for ledeburite steel cold rolls, in particular to a differential temperature quenching method for large-diameter integral ledeburite steel cold rolls. Background technique [0002] For ledeburite steel with eutectic carbide structure, after forging heat treatment, it has higher hardness and wear resistance than non-ledeburite steel, and is mainly used to manufacture work rolls of heavy-duty cold rolling mills. However, as the diameter increases, the size of the steel ingot required for processing the billet will inevitably increase, and the accumulation of carbides in the center will become more and more serious. The melting point is relatively low, and it is easy to produce overheated structures during forging or heat treatment heating. In particular, it has a high content of alloying elements - its hardenability index is high. For large-diameter (effective size exceeding 200 mm) overall ledeburite stee...

Claims

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Application Information

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IPC IPC(8): C21D9/38C21D1/18
Inventor 张玉力杨立凤杜晓强杨旭东景群社刘瑞明曹敏刘国庆
Owner SHANXI BUYEASY MACHINERY MFG
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